Kinetics of separating multicomponent mi

The study presents a model for the nonsteady separation of metals using nondispersive solvent extraction, explicitly accounting for the selective separation of multicomponent solutions and the concentration of separated components in a back-extraction phase. The separation process consists of extraction and back-extraction steps carried out in two distinct hollow-fiber modules connected through the organic phase, along with three homogenization tanks. The underlying model is based on a set of coupled differential equations that describe the mass balances of metallic solutes within the fluid phases. To utilize the model in its most straightforward form, three characteristic parameters, including two pertaining to chemical reactions and one mass-transport parameter through the hollow-fiber membrane, must be known. The validity of the mathematical model was assessed by comparing it with kinetic results from the separation of Cd/Ni mixtures, utilizing high-concentration solutions. This led to obtaining the characteristic parameters specific to this system. The results indicate that while nickel (Ni) extraction is negligible under the studied conditions, cadmium (Cd) can be efficiently extracted and shows a significant decrease in concentration within a short time frame.